added HTTP REST APIs for online loglevel adjustments:

- GET `/_admin/log/level` returns the current loglevel settings
- PUT `/_admin/log/level` modifies the current loglevel settings

CHANGELOG

@@ -1,6 +1,11 @@
 devel
 -----
 
+* added HTTP REST APIs for online loglevel adjustments:
+
+  - GET `/_admin/log/level` returns the current loglevel settings
+  - PUT `/_admin/log/level` modifies the current loglevel settings
+
 * changed default for keepNull of modifyVertex/modifyEdge to true in Gharial
 
 * renamed `maximalSize` attribute in parameter.json files to `journalSize`

Documentation/Books/HTTP/AdministrationAndMonitoring/README.mdpp

@@ -6,7 +6,11 @@ monitoring of the server.
 
 <!-- lib/Admin/RestAdminLogHandler.cpp -->
 
-@startDocuBlock JSF_get_admin_modules_flush
+@startDocuBlock JSF_get_admin_log
+
+@startDocuBlock JSF_get_admin_loglevel
+
+@startDocuBlock JSF_put_admin_loglevel
 
 
 <!-- js/actions/api-system.js -->

Documentation/DocuBlocks/Rest/Administration/JSF_get_admin_modules_flush.md

@@ -1,6 +1,6 @@
 
-@startDocuBlock JSF_get_admin_modules_flush
-@brief returns the log files
+@startDocuBlock JSF_get_admin_log
+@brief returns the server logs
 
 @RESTHEADER{GET /_admin/log, Read global logs from the server}
 
@@ -65,3 +65,54 @@ is returned if the server cannot generate the result due to an out-of-memory
 error.
 @endDocuBlock
 
+
+@startDocuBlock JSF_get_admin_loglevel
+@brief returns the current loglevel settings
+
+@RESTHEADER{GET /_admin/log/level, Return the current server loglevel}
+
+@RESTDESCRIPTION
+Returns the server's current loglevel settings.
+The result is a JSON object with the log topics being the object keys, and
+the log levels being the object values.
+
+@RESTRETURNCODES
+
+@RESTRETURNCODE{200}
+is returned if the request is valid
+
+@RESTRETURNCODE{500}
+is returned if the server cannot generate the result due to an out-of-memory
+error.
+@endDocuBlock
+
+
+@startDocuBlock JSF_put_admin_loglevel
+@brief modifies the current loglevel settings
+
+@RESTHEADER{PUT /_admin/log/level, Modify and return the current server loglevel}
+
+@RESTDESCRIPTION
+Modifies and returns the server's current loglevel settings.
+The request body must be a JSON object with the log topics being the object keys
+and the log levels being the object values.
+
+The result is a JSON object with the adjusted log topics being the object keys, and
+the adjusted log levels being the object values.
+
+@RESTRETURNCODES
+
+@RESTRETURNCODE{200}
+is returned if the request is valid
+
+@RESTRETURNCODE{400}
+is returned when the request body contains invalid JSON.
+
+@RESTRETURNCODE{405}
+is returned when an invalid HTTP method is used.
+
+@RESTRETURNCODE{500}
+is returned if the server cannot generate the result due to an out-of-memory
+error.
+@endDocuBlock
+

arangod/GeneralServer/GeneralServerFeature.cpp

@@ -521,7 +521,7 @@ void GeneralServerFeature::defineHandlers() {
       "/_admin/version", RestHandlerCreator<RestVersionHandler>::createNoData);
 
   // further admin handlers
-  _handlerFactory->addHandler(
+  _handlerFactory->addPrefixHandler(
       "/_admin/log",
       RestHandlerCreator<arangodb::RestAdminLogHandler>::createNoData);
 

arangod/GeneralServer/RestHandler.cpp

@@ -28,6 +28,8 @@
 #include "Logger/Logger.h"
 #include "Rest/GeneralRequest.h"
 
+#include <velocypack/Exception.h>
+
 using namespace arangodb;
 using namespace arangodb::basics;
 using namespace arangodb::rest;
@@ -72,6 +74,10 @@ RestHandler::status RestHandler::executeFull() {
     } catch (Exception const& ex) {
       requestStatisticsAgentSetExecuteError();
       handleError(ex);
+    } catch (arangodb::velocypack::Exception const& ex) {
+      requestStatisticsAgentSetExecuteError();
+      Exception err(TRI_ERROR_INTERNAL, std::string("VPack error: ") + ex.what(), __FILE__, __LINE__);
+      handleError(err);
     } catch (std::bad_alloc const& ex) {
       requestStatisticsAgentSetExecuteError();
       Exception err(TRI_ERROR_OUT_OF_MEMORY, ex.what(), __FILE__, __LINE__);

arangod/RestHandler/RestAdminLogHandler.cpp

@@ -24,6 +24,7 @@
 #include "RestAdminLogHandler.h"
 
 #include <velocypack/Builder.h>
+#include <velocypack/Iterator.h>
 #include <velocypack/velocypack-aliases.h>
 
 #include "Basics/StringUtils.h"
@@ -41,11 +42,18 @@ RestAdminLogHandler::RestAdminLogHandler(GeneralRequest* request,
 
 bool RestAdminLogHandler::isDirect() const { return true; }
 
-////////////////////////////////////////////////////////////////////////////////
-/// @brief was docuBlock JSF_get_admin_modules_flush
-////////////////////////////////////////////////////////////////////////////////
-
 RestHandler::status RestAdminLogHandler::execute() {
+  size_t const len = _request->suffix().size();
+
+  if (len == 0) {
+    reportLogs();
+  } else {
+    setLogLevel();
+  }
+  return status::DONE; 
+}
+
+void RestAdminLogHandler::reportLogs() {
   // check the maximal log level to report
   bool found1;
   std::string const& upto =
@@ -86,7 +94,7 @@ RestHandler::status RestAdminLogHandler::execute() {
                     TRI_ERROR_HTTP_BAD_PARAMETER,
                     std::string("unknown '") + (found2 ? "level" : "upto") +
                         "' log level: '" + logLevel + "'");
-      return status::DONE;
+      return;
     }
   }
 
@@ -246,6 +254,67 @@ RestHandler::status RestAdminLogHandler::execute() {
     // Has been ignored thus far
     // So ignore again
   }
-
-  return status::DONE;
+}
+
+void RestAdminLogHandler::setLogLevel() {
+  std::vector<std::string> const& suffix = _request->suffix();
+
+  // was validated earlier
+  TRI_ASSERT(suffix.size() > 0); 
+
+  if (suffix[0] != "level") {
+    generateError(rest::ResponseCode::BAD,
+                  TRI_ERROR_HTTP_SUPERFLUOUS_SUFFICES,
+                  "superfluous suffix, expecting /_admin/log/level");
+    return;
+  }
+
+  auto const type = _request->requestType();
+
+  if (type == rest::RequestType::GET) {
+    // report loglevel
+    VPackBuilder builder;
+    builder.openObject();
+    auto const& levels = Logger::logLevelTopics();
+    for (auto const& level : levels) {
+      builder.add(level.first, VPackValue(Logger::translateLogLevel(level.second)));
+    }
+    builder.close();
+
+    generateResult(rest::ResponseCode::OK, builder.slice());
+  } else if (type == rest::RequestType::PUT) { 
+    // set loglevel
+    bool parseSuccess = true;
+    std::shared_ptr<VPackBuilder> parsedBody = parseVelocyPackBody(&VPackOptions::Defaults, parseSuccess);
+    if (!parseSuccess) {
+      return;
+    }
+    
+    VPackSlice slice = parsedBody->slice();
+    if (slice.isString()) {
+      Logger::setLogLevel(slice.copyString());
+    } else if (slice.isObject()) {
+      for (auto const& it : VPackObjectIterator(slice)) {
+        if (it.value.isString()) {
+          std::string const l = it.key.copyString() + "=" + it.value.copyString();
+          Logger::setLogLevel(l);
+        }
+      }
+    }
+    
+    // now report current loglevel
+    VPackBuilder builder;
+    builder.openObject();
+    auto const& levels = Logger::logLevelTopics();
+    for (auto const& level : levels) {
+      builder.add(level.first, VPackValue(Logger::translateLogLevel(level.second)));
+    }
+    builder.close();
+
+    generateResult(rest::ResponseCode::OK, builder.slice());
+  } else {
+    // invalid method
+    generateError(rest::ResponseCode::METHOD_NOT_ALLOWED,
+                  TRI_ERROR_HTTP_METHOD_NOT_ALLOWED);
+  }
 }

arangod/RestHandler/RestAdminLogHandler.h

@@ -45,6 +45,10 @@ class RestAdminLogHandler : public RestBaseHandler {
   //////////////////////////////////////////////////////////////////////////////
 
   status execute() override;
+
+ private:
+  void reportLogs();
+  void setLogLevel();
 };
 }
 

arangod/RestHandler/RestBaseHandler.cpp

@@ -43,6 +43,25 @@ RestBaseHandler::RestBaseHandler(GeneralRequest* request,
                                  GeneralResponse* response)
     : RestHandler(request, response) {}
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief parses the body as VelocyPack
+////////////////////////////////////////////////////////////////////////////////
+
+std::shared_ptr<VPackBuilder> RestBaseHandler::parseVelocyPackBody(
+    VPackOptions const* options, bool& success) {
+  try {
+    success = true;
+    return _request->toVelocyPackBuilderPtr(options);
+  } catch (VPackException const& e) {
+    std::string errmsg("VPackError error: ");
+    errmsg.append(e.what());
+    generateError(rest::ResponseCode::BAD, TRI_ERROR_HTTP_CORRUPTED_JSON,
+                  errmsg);
+  }
+  success = false;
+  return std::make_shared<VPackBuilder>();
+}
+
 void RestBaseHandler::handleError(Exception const& ex) {
   generateError(GeneralResponse::responseCode(ex.code()), ex.code(), ex.what());
 }

arangod/RestHandler/RestBaseHandler.h

@@ -32,6 +32,7 @@ namespace arangodb {
 class TransactionContext;
 
 namespace velocypack {
+class Builder;
 struct Options;
 class Slice;
 }
@@ -66,6 +67,9 @@ class RestBaseHandler : public rest::RestHandler {
   void generateCanceled();
 
  protected:
+  /// @brief parses the body as VelocyPack
+  std::shared_ptr<arangodb::velocypack::Builder> parseVelocyPackBody(arangodb::velocypack::Options const*, bool&);
+
   template <typename Payload>
   void writeResult(Payload&&, arangodb::velocypack::Options const& options);
 };

arangod/RestHandler/RestVocbaseBaseHandler.cpp

@@ -636,25 +636,6 @@ bool RestVocbaseBaseHandler::extractBooleanParameter(char const* name,
   return def;
 }
 
-////////////////////////////////////////////////////////////////////////////////
-/// @brief parses the body as VelocyPack
-////////////////////////////////////////////////////////////////////////////////
-
-std::shared_ptr<VPackBuilder> RestVocbaseBaseHandler::parseVelocyPackBody(
-    VPackOptions const* options, bool& success) {
-  try {
-    success = true;
-    return _request->toVelocyPackBuilderPtr(options);
-  } catch (VPackException const& e) {
-    std::string errmsg("VpackError error: ");
-    errmsg.append(e.what());
-    generateError(rest::ResponseCode::BAD, TRI_ERROR_HTTP_CORRUPTED_JSON,
-                  errmsg);
-  }
-  success = false;
-  return std::make_shared<VPackBuilder>();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief prepareExecute, to react to X-Arango-Nolock header
 ////////////////////////////////////////////////////////////////////////////////

arangod/RestHandler/RestVocbaseBaseHandler.h

@@ -266,12 +266,6 @@ class RestVocbaseBaseHandler : public RestBaseHandler {
 
   bool extractBooleanParameter(char const* name, bool def) const;
 
-  //////////////////////////////////////////////////////////////////////////////
-  /// @brief parses the body as VelocyPack
-  //////////////////////////////////////////////////////////////////////////////
-
-  std::shared_ptr<VPackBuilder> parseVelocyPackBody(VPackOptions const*, bool&);
-
  protected:
   //////////////////////////////////////////////////////////////////////////////
   /// @brief request context